Essential hypertension is thought to be associated with insulin resistance. The mechanism by which insulin resistance may be associated with hypertension or whether or not it is of pathophysiological consequences remains unknown. Growing evidence suggests that hyperinsulinemia per se may be an independent risk factor for the development of coronary artery disease. This purpose of this study is to study the effects of Amlodipine, a new second generation calcium channel blocker, vs enalapril on glucose metabolism and insulin sensitivity in patients with mild to moderate essential hypertension.